When purchasing or building a home a lot of people don't pay attention to one of the most important things: insulation. If we don't see it, it doesn't mean that it's not important. After inspecting our home, we noticed the roof insulation was very thin and in bad shape. Also, our HVAC unit was located in the attic, above the insulation, which means that we were cooling and heating outside air. This is very bad for your power / gas bill. The HVAC unit should ALWAYS be located in a conditioned space.
On all the homes we design, we always specify to use spray foam insulation between the roof rafters. The spray foam not only provides the R-Value required by Code but also seals any gap and/or opening where air might infiltrate.
There are a few companies in Atlanta that install spray foam in your attic: they vacuum your existing insulation (with all the debris), disinfect the attic and spray a minimum 6" of foam to the underside of the roof decking.
See below our attic.